The invention is directed to a process for the separation of bis pentaerythritol monoformal from crude pentaerythritol.
In the customary production of pentaerythritol by condensation of formaldehyde with acetaldehyde there is formed a crude pentaerythritol contaminated by various byproducts. A particularly disturbing product is bis pentaerythritol monoformal. The content of this byproduct generally amounts to about 2 to 5%.
It is known to remove the bis pentaerythritol monoformal from the crude pentaerythritol by treating aqueous solutions of the crude pentaerythritol at a temperature of 50.degree. to 150.degree. C. with a strongly acid cation exchange resin (Hercules British Pat. No. 799,182) or at a temperature of 150.degree. to 300.degree. C. under pressure with a cracking catalyst (Maury U.S. Pat. No. 2,939,837). These processes are expensive and therefore are little suited for use on an industrial scale.